Nonresidual insecticides may be dispensed
through fogging as aerosols in food produc-
tion areas when food is not exposed. This tech-
nique is used to apply pyrethrins, which are
usually synergized with piperonyl butoxide.
Other common insecticides are pyrethroids.
Aerosol applications, which effectively kill
flying and exposed insects, are frequently
dispensed on a timed-release basis at a pre-
arranged convenient time when food produc-
tion and contact does not occur.
Fumigants are used in the food industry
primarily to control insects that attack stored
products. Their primary feature is the ability
to reach hidden pests. These compounds are
normally used for space treatment, typically
on weekends, when processing operations are
ceased for safety precautions. To ensure ade-
quate dispersion, fumigants are often applied
with air-moving equipment, such as ventila-
tion machinery or fans. The major mode of
fumigant action is through the activation of
respiratory enzymes within the pest. Oxygen
assimilation is blocked or delayed by most
fumigants. The following chemicals are com-
mon fumigants for insects:
●Phosphine: The principal active com-
pound in this fumigant is aluminum
phosphide, which is usually contained in
a permeable package or in pellets. This
method of use permits controlled con-
tact of the phosphine with moisture in
the air to release hydrogen phosphide
(phosphine), the active ingredient. This
gas is very flammable. Instructions pro-
vided for use and storage provided by
the supplier should be followed.
●Methyl bromide: This nonflammable
fumigant is widely used. Methyl bromide
penetrates effectively and acts as a respira-
tory toxin, apparently absorbed through
the insect’s cuticle. Regulators have evalu-
ated this fumigant and it appears that it
will be phased out in the future.●Ethylene oxide:This nonresidual fumi-
gant is normally mixed with carbon
dioxide in a ratio of 1:9 (by weight) to
reduce flammability and explosiveness.
This insecticide, most frequently used
for stored commodities, should be
applied through a professional pest con-
trol operator.
●Carbonyl sulfide: This compound has
been found to be toxic to a large number
of species of stored-product insects. It
has been patented as a fumigant for con-
trol of insects and mites in post-harvest
commodities. According to Brunner
(1994), carbonyl sulfide has many char-
acteristics indicating that it could replace
methyl bromide or phosphine, or both,
under some circumstances. It is environ-
mentally friendly, with good penetration
and aeration characteristics. It is versa-
tile, being toxic in short exposure peri-
ods or for a longer exposure time. This
fumigant shows no adverse effects on
seed germination and is an effective
fumigant for other commodities.Other Chemical Methods of Insect Control
Other potential methods of insect control
include the use ofbaits. Baits are a combi-
nation of insect-attracting foods, such as
sugar, and an insecticide.
Although baits are not always as conven-
ient to use as other methods, they can be
effective in controlling inaccessible areas of
ant and cockroach infestations and in reduc-
ing outside fly populations. Because baits are
a poisonous food, special precautions should
be exercised in their use and storage. Com-
mercial dry granular baits should be scat-
tered thinly over feeding surfaces daily, or as
needed, to provide initial knockdown and
control of populations. Granular fly baits
are satisfactory for outdoor use only. Liquid
baits consist of an insecticide in water with
an attractant such as sugar, corn syrup, orPest Control 241